It is known to propel a marine vehicle utilizing a propeller assembly mounted on a rotatable drive shaft. The propeller assembly includes a plurality of propeller blades extending radially from a central hub. A motor rotates the drive shaft that, in turn, rotates the propeller blades propelling the marine vehicle through the water. Typically, the propeller assembly is constructed as a unit wherein the propeller blades and the central hub are mounted or removed from the drive shaft in unison. Alternatively, in order to reduce the time and costs associated with replacing the propeller blades, it has been contemplated to provide a propeller assembly for a marine engine wherein the propeller blades project from a propeller housing that is removable from a central hub.
By way of example, Chen, U.S. Pat. No. 5,967,751 discloses a marine propeller assembly that includes a central hub secured to the propeller shaft and having three or more axially extending keys on the outer surface thereof. A propeller housing includes an inner surface having three or more pairs of lobes for forming keyways that receive the keys of the central hub. A retainer disc is threaded on a propeller shaft and includes a plurality of angularly spaced ears for engaging with the lobes on the inner surface on the propeller housing in order to prevent the propeller housing from being disengaged from the central hub.
While the advantages of a removal propeller housing are readily apparent, it can be appreciated that it is often highly desirable to retain the propeller assembly on the propeller shaft in such a manner as to prevent any unnecessary movement of the propeller assembly that may reduce the overall efficiency of the drive system of the marine vehicle. However, during such circumstances when the propeller blades engage a fixed object in the water such as a rock or the like, it may become necessary for the drive shaft of the marine vehicle to become disengaged from the propeller housing in order to prevent damage to the drive system of the marine vehicle. Consequently, it is desirable to provide a propeller assembly that disengages from the drive shaft in response to a predetermined force thereon. However, once a propeller assembly has disengaged from the drive shaft, the operator typically must replace the central hub or a component of the hub before the propeller assembly can be used again. Further, it has been noted that most damage to a drive system occurs within 5° of rotation by the propeller shaft after the propeller assembly stops rotating. For these reasons, it is highly desirable to provide a propeller assembly that permits continued rotation of the propeller shaft for at least 5° after the propeller housing disengages from the shaft.
In addition, it is known that the drive shafts driven by the various motors for marine vehicles differ depending upon the manufacture. Consequently, individual propellers must be provided for the drive shafts of each motor brand. Maintaining an inventory of specific propellers for each brand of motor requires significant storage space and may be cost prohibitive.
Therefore, it is a primary object and feature of the present invention to provide a propeller assembly which permits limited continued rotation of the spindle and propeller shaft before disengaging the propeller shaft from the propeller assembly.
It is still a further object and feature of the present invention to provide a propeller assembly that may be simply and easily mounted on and removed from the drive shaft of a marine vehicle.
It is a still further object and feature of the present invention to provide a propeller assembly that may be easily adapted for mounting on the drive shafts of different manufacturers' motors.
It is a still further object and feature of the present invention to provide a propeller assembly that is simple and inexpensive to manufacture.
In accordance with the present invention, an improvement in a propeller assembly having a housing structure connectable to a rotatable propeller shaft of a watercraft is provided. The housing structure extends along a longitudinal axis and has an inner surface defining passageway therethrough. The improvement includes a spindle receivable in the passageway of the housing. The spindle has an inner surface defining a passageway for receiving the propeller shaft therethrough and an outer surface. The improvement also includes plurality of circumferentially spaced, longitudinally extending fin pairs. Each fin pair includes a first fin extending from the outer surface of the spindle and a second fin extending from the outer surface of the spindle at a predetermined angle to the first fin.
A bushing is molded over the outer surface of the spindle. The bushing includes an outer surface engageable with an inner surface of the housing structure. The bushing is formed from a resilient material and has a generally square-shaped cross section and rounded corners. The inner surface of the spindle includes a plurality of longitudinally extending splines.
The inner surface of the housing structure has a generally square-shaped cross section and at least four fin pairs extend from the outer surface of the spindle. The inner surface of the housing structure is defined by first, second, third and fourth sidewalls. The first and second sidewalls is generally parallel to each other. The third and fourth sidewalls are generally parallel to each other and generally perpendicular to the first and second spaced sidewalls. The first fin of a first fin pair is directed toward the first sidewall of the inner surface of the housing structure and the second fin of the first fin pair is directed toward the third sidewall. The first fin of a second fin pair is directed toward the first sidewall of the inner surface of the housing structure and the second fin of the second fin pair is directed toward the fourth sidewall. It is contemplated for the fin pairs to fragment from the outer surface of the spindle in response to a predetermined force thereon.
In accordance with a further aspect of the present invention, a propeller assembly is provided for mounting on a rotatable propeller shaft of a watercraft. The propeller assembly includes a housing structure extending along a longitudinal axis. The housing structure includes an outer surface and an inner surface defining a cavity having a polygonal-shaped cross-section defined by at least one corner and at least one sidewall. A bushing assembly is receivable in the cavity of the housing structure. The bushing assembly includes a spindle having an inner surface defining a passageway for receiving the propeller shaft therethrough and an outer surface having a plurality of circumferentially spaced fin pairs extending therealong. Each fin pair includes a first fin extending from the outer surface of the spindle and a second fin extending from the outer surface of the spindle at a predetermined angle to the first fin. A bushing is positioned between the spindle and the inner surface of the housing structure.
The bushing is formed from a resilient material and the inner surface of the housing structure has a generally square-shaped cross section. The at least one sidewall of the inner surface of the housing structure includes first and second spaced sidewalls being generally parallel to each other and third and fourth sidewalls being generally parallel to each other and perpendicular to the first and second spaced sidewalls. The first fin of a first fin pair is directed toward the first sidewall of the inner surface of the housing structure and the second fin of the first fin pair is directed toward the third sidewall. The first fin of a second fin pair is directed toward the first sidewall of the inner surface of the housing structure and the second fin of the second fin pair is directed toward the fourth sidewall. It is contemplated for the fin pairs to fragment from the outer surface of the spindle in response to a predetermined force thereon.
In accordance with a still further aspect of the present invention, a propeller assembly is provided for mounting on a rotatable propeller shaft of a watercraft. The propeller assembly includes a housing structure extending along a longitudinal axis. The housing structure includes an outer surface and an inner surface defining a cavity. The inner surface is defined by first, second, third and fourth sidewalls. The first and second sidewalls are generally parallel to each other. The third and fourth sidewalls are generally parallel to each other and perpendicular to the first and second spaced sidewalls. A bushing assembly includes a spindle having an inner surface defining a passageway for receiving the propeller shaft therethrough and an outer surface. A first fin pair extends from the outer surface of the spindle and has a first fin is directed towards the first sidewall of the inner surface of the housing structure and a second fin directed towards the third sidewall. A second fin pair extends from the outer surface of the spindle and has a first fin is directed towards the first sidewall of the inner surface of the housing structure and a second fin directed towards the fourth sidewall. A third fin pair extends from the outer surface of the spindle and has a first fin is directed towards the second sidewall of the inner surface of the housing structure and a second fin directed towards the third sidewall. A fourth fin pair extends from the outer surface of the spindle and has a first fin is directed towards the second sidewall of the inner surface of the housing structure and a second fin directed towards the fourth sidewall.
A bushing is positioned between the spindle and the inner surface of the housing structure. The bushing is formed from a resilient material.